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svs tune mode 20 , 16 or 12hz ???

paulst10

Distinguished Member
http://www.hometheaterforum.com/htf...eadid=144887&perpage=30&display=&pagenumber=1 .... 17 pages long this one .. :eek:

http://www.avsforum.com/avs-vb/showthread.php?t=605496

been looking at these waterfall threads recently and have noticed that loads of films seem to have a lot of bass content well below 20hz, take the matrix revolutions for eg: during the water explosion there seems to be extremely loud bass between 9hz - 14hz (see attach) .... so we must be missing out on some serious low end stuff unless you have it tuned to 12hz.

so, i was wondering what tune mode everybody is using and for what reason? do you like the output of the 20hz or the deep extension of the 12hz tune (which i have been told goes down to 9hz :D )

i currently have it switched to 16hz, but im gonna have a little experiment with 12hz. does anyone know if plugging specific ports makes any diference ?
 

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Andywilliams

Established Member
Hi
just be careful at what volume you play at with it in 12hz as if you go too loud you will bottom the driver out.
I run my ultra at 16 hz one port blocked which seems to me the best sounding option.
 

Nimby

Distinguished Member
Speaking generally from reading a few reviews on the subject of SVS tuning the 16Hz tune seems to offer the best of all worlds.

20 Hz has much more wallop for films but may leave the music fan feeling rather full after the meal.

The 12Hz setting might suit those who listen to music and film in a small room but this tuning restricts maximum output levels and may lead to port noise. It also places heavy loading on the driver. Low frequencies at high levels need enormous cone movements. Trying to squeeze extra dBs out of the 12Hz tune to try and lift such very low frequencies to a more noticeable level may be impossible.

If I owned a tri-port SVS I'd go entirely by the in-room response on sine wave testing. The flattest in-room response is (in my opinion) always more desirable over maximum SPLs at a particular frequency hump.

If you want high levels at such low frequencies the only real answer is more subwoofers. The more the better since this will also lower distortion and increase the dynamics without risking the seperate units. Preferably in a concrete bunker. (with a handy sick bowl) :)
 

Hungry Horace

Established Member
I have a PB12 Plus, and I use it in 12hz mode for music, the difference between 16, and 12hz isn't huge but it does sound a tad better in 12hz tune. 12hz is also ok for movies at moderate sound levels, but I do prefer either 16 or 20hz tune when I feel like being properly shaken.

The variable tuning is one of the things I really like about the Plus, if you're not using its SPL capabilities, you can trade them in for extension so that as little power as possible is untapped :)
 

chrisgeary

Prominent Member
i used to have mine tuned to 12hz but recently tried the 16hz option. i still get in room response down to 14hz and the extra 2 or 3db is useful. in both living rooms i have had SVS subs, i have never tallied up the subsonic filter against the tuning point:

at 12hz tuning, i was using a 20hz ss filter
at 16hz tuning, i am using a 25hz ss filter.

for reasons, im guessing are, due to cabin gain, the stock tune creates a big peak when used with the corresponding ss filter - it can be as much as 6db more than it should be. so using a higher ss filter helps.

i, too, love extension, and am still weighing up whether i prefer 16hz or 12. and yes, in 12hz tune, you do get usable extension down to 10hz. i watched plenty of movies at -10db using this tune, but with 20hz ss filter set. i never got my sub to bottom out at -5db using those settings in a 6m x 4m room. perhaps the ss filter setting is the key. it would easily have bottomed out had i been using the 12hz ss filter setting, but there is way too much sub 16hz SPL in room, IME, which tended to muddy the sound a little.
 

Timbo21

Prominent Member
I find 16hz gives the flattest response for my room.
 

Bone Daddy

Established Member
Yep 16hz with one port blocked gives the optimum performance for me - done all the other ones and this seems to give the best all round bang for the buck.
 

AngelEyes

Distinguished Member
I only ever tried 20 & 16hz as I either didn't receive 2 port bungs or lost one the day I got it :mad:

16hz is a lot flatter than the 20hz so it seemed like the best bet for me. Maybe I'll try fiddling again sometime but last time it took a whole weekend and with kids in the house... forget it :)
 

chrisgeary

Prominent Member
out of interest, which ss filter do you guys use with which tune?
 

Ettepet

Established Member
16Hz rules! :thumbsup:
 

paulst10

Distinguished Member
chrisgeary said:
out of interest, which ss filter do you guys use with which tune?

iv always gone by the rules and used the matched ss filter + tune, then yesterday i mixed n matched for a bit, and resorted back to 16hz with one port closed.

i plan to get an sms-1 soon which has a calibrated mic, i dont really trust using the spl metre, then i can hopefully see what filter/tune is best for my room
 

Ettepet

Established Member
chrisgeary said:
out of interest, which ss filter do you guys use with which tune?

To people in general:

Please be careful with using non-matching filter settings, you may damage your driver or blow up your amp otherwise! :eek:
 

chrisgeary

Prominent Member
Ettepet is right. You should be cautious. I had a longish discussion with Ron/Tom at SVS and their official recommendation is to match ss filter with tune. However, they did agree that it is OK to use a higher subsonic filter setting (in relation to the port tune) but stated clearly that I should NEVER USE A LOWER SUBSONIC FILTER SETTING.

The rationale behind it is the lower subsonic filter allows the driver to move move at lower frequencies. The port bungs effectively retard that movement somewhat. Thus if you had all three ports open but chose a 12hz subsonic filter setting, the driver could move much further than the design intended it to and not only hit its end stops, but hit them so hard as to damage the driver, voice coils etc.

However, using a higher subsonic filter setting compared to the port tune prevents the driver from moving more at lower frequencies. This seems to work well controlling cabin gain around the port tune frequency and is safe to do.

I think the rule of thumb officially is to match subsonic setting to port tune but unofficially you can safely use an equal or higher subsonic filter setting compared to port tune.
 

Andywilliams

Established Member
Well in my room having tried the variable settings it sounds best at 16hz and matching ss filter setting.
 

Gary_W

Established Member
With my Ultra, I've only tried 16Hz and 20Hz. 16Hz won. You feel the difference on material such as 'War of the Worlds'.

I've always matched the port tune to the number of ports bunged; it may be scaremongering to suggest that it will damage the sub, but that's over a grands worth of gamble I am not willing to take. Especially when doing as the manual suggests gives good results.

Gary
 

derekn

Established Member
16Hz and one port blocked on my PB Ultra works best in my room - both soundwise and on SPL graphs.
 

AngelEyes

Distinguished Member
Yay, I found my missing port bung and tried out the 12hz setting on WOTW...

all I can say is WOW the difference was fantastic (bear in mind I have a new processor since I last listened...). the difference was pretty dramatic and in such a small room I don't think I will miss any output, if anything the feeling in the chest is even greater than 16hz.

I did get a few thumping noises that although not obviously 'mechanical' didn't sound as if they are included in the soundtrack. Could this be clipping of the signal from my BFD? The red light was pretty much on permanantly during some of the louder scenes (tripod rising etc.).

I don't think it was bottoming out as I didn't here a distinct noise which I have read something you can't really mistake.
 

paulst10

Distinguished Member
hi, angel. have you tried playing the same content with 16hz, to see if you the same noise?
 

stevefish69

Prominent Member
Nimby said:
Unexpected noises sound like a warning sign. I wouldn't risk it. :oops:

I had my 20-39 Tuned to 16Hz but pulled the port after getting some distracting noises at high SPL. Never had a problem since, even at higher volumes :D

Steve
 

AngelEyes

Distinguished Member
paulst10 said:
hi, angel. have you tried playing the same content with 16hz, to see if you the same noise?

No, not yet but i know the volume etc so i will give it a blast some time soon. I can't tell you the -db as my processor doesn't display it but the volume was 70 which is loud. I couldn't sit through most films at that volume.
 

badbob

Banned
If you really want the lowest end performance you should be looking at the SS or the 16hz tubes, not a box sub or 25hz tube with both ports plugged.
 

chrisgeary

Prominent Member
badbob said:
If you really want the lowest end performance you should be looking at the SS or the 16hz tubes, not a box sub or 25hz tube with both ports plugged.

why? i find this statement rather odd. i have a box sub and it performs exactly the same as the 20-30PC+.
 

Nimby

Distinguished Member
I think badbob was suggesting the optimum models of SVS sub needed to provide ultra-low frequencies at reasonable levels. The PB12 models are more like the 25-31 rather than the 20-39 (or 16-46) I believe. Probably tied up with the maximum physical length of port allowed in the confines of a box. Even then they use elbows (bends) to extend the port length(s) in the boxes. The tubes were probably optimised for the physical length of reflex port that would fit into a certain height of cylinder. I'd still like to hear what a 46" high PC Ultra with a single large port can do. Perhaps that's the SS? :)
 

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